[SIZE=12pt]I wont use ANYTHING that is electric with my horses when it comes to water, dont use any duct tape either. What we do, (and I live in northern Wisconsin where we get some brutally COLD winters,) is Bob (hubby) built a insulated box that goes around my oval rubber water tank, and he also took 2 tanks one is a little bit bigger then the inside one..and took that foam insulating spray stuff, put it all over the outside of the smaller tank and then very quickly set that tank inside the little bit bigger tank, so it was like a homemade insulated tank. Between that being insulated and the box around it being double layered and insulated, it keep my water from freezing really bad..On the coldest of nights I will get a thin layer of ice on it but its nothing to break thru and remove it, but usually what I do is just add a few pails of hot water and its melted. My tank sits inside our run-in, so its not completely out in the open. You do have to work fast with this spray stuff, and make sure that there is nothing exposed for the horses to get at. This has worked for me and is safe for the horses. [/SIZE]